It is known that, on board an aircraft, it is necessary to have hot air available to perform certain functions, such as air conditioning in the cockpit and the passenger cabin or for deicing certain parts of the aircraft.
It is also known that this hot air is taken from the turbojet engines of the aircraft and has to be cooled significantly before it can be used. To do this, a heat exchanger is provided, this generally being known as a pre-cooler, in which the hot air bled from the central generator of the turbojet engine is cooled by cold air from the fan duct.
Of course, during this heat exchange process, not only is the hot air bled from the central generator cooled by the cold air of the fan duct, but also this cold air is heated up by said hot air. It is therefore necessary to discharge this heated cold air to the outside.
In general, this heated cold air is discharged to the outside at the upper part of the engine suspension pylon, in front of the leading edge of the wind structure, and this leads to turbulence and aerodynamic disturbances that increase the drag of the aircraft.
To avoid this disadvantage, American document U.S. Pat. No. 5,729,969 proposes discharging the heated cold air into the annular cross section chamber formed between the central hot stream generator and the inner fairing of the fan duct, which chamber is then equipped with at least one ejection orifice directed toward said cold stream. However, an arrangement such as this carries the risk of disturbing the thermal regulation of the hot stream generator and therefore of accelerating turbine engine wear.